Showtime

The power of the space bar

A laptop running Showtime: the show’s run sheet on the left, and what the current stage does on the right. Showtime. Laptop running Showtime A small comedy club stage with a stool and a mic. The laptop running Showtime, shown to the left, is linked to two moving-head lights, a speaker, a TV with a Chromecast, a cue screen facing the act, and a camera in the audience. Each press of the space bar moves the show to its next stage. Chromecast Tracking Show 1A2B Comedy Night, 8:00 PM DMX lights TV Speakers Cue screen, facing the act Camera 1 2 3 4 5

  1. DMX lights

    Stop scanning the room and turn to the act in their walk-on colour.

  2. Walk-on sting

    Takes over from the pre-show playlist.

  3. TV

    Shows the act’s name, the interval poll and its results: a web page on a Chromecast. In the interval, the laptop ticks off mailing list sign-ups.

  4. Cue screen

    Faces the act and counts down the time they have left.

  5. Camera

    Starts recording the set.

How DMX works

DMX is how a lighting desk tells stage lights what to do. Move a fader and watch both lights follow.

A lighting desk, or a Chromebook running Showtime with a USB-to-DMX dongle, sends DMX down a cable to two par cans, one after the other. The back of each par can shows its DMX address. SCANNER SCENE MASTER BLACKOUT DMX512 Showtime. Lights SCENES USB → DMX Lighting desk Chromebook Dongle MIDI controller Par A Par B terminator
Scenes
Scanner (each one is 16 channels)
SCENES
See the numbers Showtime sends

  1. Lighting desk

    Each fader sends a number from 0 (off) to 255 (full). Master turns everything up or down, Blackout turns everything off, and the scene buttons bring back saved looks.

  2. MIDI controller

    Plugs into the Chromebook. Each pad presses one of Showtime’s scene buttons, so you can run the show without looking at the screen.

  3. Chromebook

    Showtime has a button for each lighting scene. Press one and it works out which numbers to send to which light.

  4. Dongle

    Plugs into the Chromebook’s USB port and turns those numbers into a DMX signal.

  5. DMX cable

    Plugs into the desk’s DMX out and carries the signal to the first light, then on to the next.

    Carries the signal to the first light, then on to the next.

  6. Lights

    Each light follows 4 channels: red, green, blue and white. Mix them to make any colour. Lights that follow the same channels always match.

Is there a simpler way?

Yes. Plug a USB-to-DMX dongle into a Chromebook and open Showtime. Instead of faders and channel numbers, you get a button for each scene.

Showtime sends the same DMX signal down the same cable, so the lights can’t tell the difference.